This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Tuners and tuner systems, such as those used in satellite receiver set top boxes, have increasingly become more complex. For instance, multiple tuners can be used to simultaneously provide separate received signals to hard disk drives for recording and storage and to external display devices such as televisions as well as to other rooms in a home. Further, satellite service providers have increased capability by adding additional channel capacity as well as new signal modulation formats. The increased signal capability may require the tuners and tuner systems to operate with signals having a large variation in performance requirements and input conditions. The additional complexity and capability has subsequently strained the design requirements for the tuners and tuner systems.
In order to address the added complexity of using multiple tuners in a set top box, a signal power splitter is often used to provide the received signals to each individual tuner. However, simple signal power splitters can degrade the performance of the tuners and tuner system. In many cases the degradation results in performance that is unacceptable over the entire possible signal reception range, particularly given the added capability requirements.
One possible solution for splitting the input signal to more than one tuner in a set top box involves adding an extra amplifier to provide signal gain and attempt to overcome the performance degradation of the signal power splitter. In order to meet the performance requirements over all possible signal conditions using the extra amplifier, some form of signal level control of the signals provided to the individual tuners in the tuner system is required. As a result, the amplifier is typically a continuously variable gain amplifier.
The additional control necessary to operate a continuously variable amplifier further increases the complexity of the tuner system. In addition, variable gain amplifiers often introduce performance degradation of their own into the tuner system and are more costly than an alternative fixed gain amplifier. In order to address the issues with these increasing requirements on the tuner system, a solution is sought that permits a cost effective low complexity solution for controlling signal level in a tuner system over a wide range of signal requirements.